Straight bar knitting machines



E. START ET AL STRAIGHT BAR KNITTING MACHINES Aug. 18, 1959 3 Sheets-Sheet 1 Filed Feb. 15, 1954 Inventors: E RHES-r S ART FWD LEO/MRO BRowH y J FL.

1959 E. STAR-T ETAL 2,899,811-

STRAIGHT BAR KNITTING MACHINES Filed Feb. 15, 1954 3 Sheets-Shed 2 fl, H

w l \g "1mg Q 1 k il INVENTORS y Lea hard Brown Aug. 18, 1959 START" ETAL 2,899,811

' STRAIGHT BAR KNITTING MACHINES Filed Feb. 15, 1954 I 3 Sheets-Sheet 3 37 lllll llllll INVENTORS BY Ltonq. w

STRAIGHT BAR KNITTING MACHINES Ernest Start, Wilford, Nottingham, and Leonard Brown, Nottingham, England, assignors to William Cotton Limited Application February 15, 1954, Serial No. 410,384

Claims priority, application Great Britain August 24, 1953 7 Claims. (Cl. 66-126) This invention is for improvements in or relating to straight bar knitting machines provided with fashioning mechanism and has particular but not exclusive reference to underwear and outerwear or pant frames on which it is required to knit various yarns and in particular soft woollen spun yarns such for example as cashmere and lambs wool. A disadvantage which it is an object of the invention to overcome is that of faults which are likely to occur at the selvedges of the fabric to different degrees which are in general greatest when narrowing and somewhat less when non-fashioning and widening. The faults in question are double looping, pressing-off of loops and splitting of yarn at the'selvedges and they occur for the basic reason of old selvedge loops and new selvedge thread not being accurately positioned on the selvedge needles for the beard points to be pressed accurately between them. The cause of this is lack of adequate tension on the fabric at the selvedges such that the tension on the yarn being fed tends to draw the old loops round the needles and upset the positioning of the old loops and new yarn on the needles, and this tension on the selvedges cannot be increased to obviate the fault without deleteriously affecting the remainder of the fabric. It is customary in said machines to provide What is known as snapping tackle comprising an automatically movable yarn tensioning arm between an adjustable yarn tensioner and the thread carrier for the purpose of effecting some control of the yarn during the knitting cycle to allow for needle movements by applying and relaxing tension on the yarn with a small extra draw-off from the yarn supply, but although it might be thought that this control could prevent the pulling action on the fabric by the yarn tension, it is found in practice that the control by the snapping tackle is not adequate for the purpose.

The invention provides a method of controlling selvedging on a straight or knitting machine which consists in reducing the tension on the yarn in such manner as to ensure accurate location of old selvedge loops and new selvedge yarn each side the pressing points of the beards. The tension on the yarn may be reduced by any suitable means functioning at any suitable time providing that the yarn has little or no tension on it whilst at least selvedge needles have yarn sunk between them. More specifically the method consists in drawing off an additional length of yarn from the supply at a location between the existing snapping tackle arm and the thread carrier whilst the yarn is prevented from pulling on the selvedge loops and at a suitable time completely releasing the tension on the additional yarn such that it hangs freely from the snapping tackle arm to the carrier and is capable of being drawn freely through the carrier during its initial movement until the yarn has been sunk between selvedge needles by at least one sinker. For this purpose when constant lead mechanism is in use the additional yarn drawn is of a length slightly greater than When the lead is variable as for instance with frictionally ice driven carriers suitable mechanism for example under control of selvedge stops may be employed whereby the length of additional yarn drawn may be similarly variable. By this means pulling of old selvedge loops by the yarn is avoided and desired accurate positioning of old selvedge loops and new selvedge yarn is obtained and maintained whilst the beards are pressed thereby avoiding the aforesaid selvedge faults. After the sinking of the yarn at the selvedges, the yarn is sunk under normal tension for the remaining needles. A subsidiary advantage of the above arrangement is that it is effective when needles'are employed at a higher level than is customary which is desirable to enable satisfactory running-on of a starting length of rib fabric.

In a convenient arrangement the additional length of yarn is drawn off the supply at a stage in knitting after the dividing sinkers have been advanced (i.e. after the commencement of the knitting cycle) sufiiciently to lock the yarn to the needles and thereby prevent pull on the yarn away from the needles causing a pull on the loops. The full required additional length of yarn may be drawn in one or more steps during the knitting cycle, with similar operation of snapping tackle, either to allow for needle movements or for yarn to be drawn off the supply for such purpose, or there may be a combination of such arrangements. The additional yarn is maintained tensioned until all the sinkers have been retracted immediately prior to the commencement of a new course and the tension is then removed such that the yarn is completely relaxed when the carrier sets in i.e. commences its traverse. Consequently the action of the carrier during the earliest part of its movement results in the major part of the slack additional yarn being taken up i.e. whilst the carrier traverses for substantially the extent of its lead over the advancing sinkers; then with the additional yarn still without the normal tension on it, the yarn is sunk between selvedge needles by at least one sinker, and maybe two or more, so that the selvedge loops are sunk with substantially no tension on the yarn, with the advantageous result referred to.

The draw-off of the additional yarn may be efiected by any suitable yam-drawing device acting between the said adjustable tensioner and the needles, such for example as a pivoted arm or a modified snapping tackle arm, which may be adjustable, and it may be operated at the required time by any suitable operating means, such for example as a cam and truck lever means in timed relation with the operation of the sinkers.

The above and other features ofthe invention set out in the appended claims are incorporated in the construction which will now be described, as specific embodiment with reference to the accompanying drawings in which: Figure 1 is a somewhat diagrammatic cross sectional view of snapping tackle incorporating means for selvedging control according to the invention.

Figure 2 is a similar view to Figure 1 showing a modification;

Figure 3 shows selvedge stop control mechanism in elevation; and

Figure 4 shows a detail of the selvedge control mechanism in plan view.

Referring now to the drawing, yarn Y is shown extending in known manner upwardly, at the right in the drawing, from a supply cone and passing horizontally through spaced eyelets 1 and 2 in bars 3 and 4 (extend ing between spaced support brackets 5, 6) and yarn tensioner 7, and next through a snapping tackle arm 8 and down to a thread carrier. The yarn tensioner 7 is for determining the basic tension on the yarn for normal knitting and the snapping tackle is for effecting some control of the yarn as previously referred to including a small additional draw-off of yarn.

for a rocking movement.

oted device 9 are disposed such that the cross bar part -9b:at the rear end of the'device is normally close to the yarn fY at the opposite side thereof to a rod 1l-snpported by arms 12 from said brackets. Therefore when therod is rocked to lift the free end of the snapping tackle arm 8, it also lifts and swings the device 9 in the direction of-the adjacent yarn Y and in consequence of this the yarn Y is kinked to thereby'draw an additionallength of yarn. This additional length of yarn is drawn from the supply by virtue of the fact that-the rocking rod ltiis caused to operate atatime after the yarn for one course. has: been laid and locked to the needles by the advancement of the divider sinkers i.e. after the commencement of the knitting cycle for that course, and it may be operated in two steps as shown by the two rises 13, 14 on cam which eifects the rocking of rod 10 throughthe medium of truck'lever and mechanismindicated generally by reference numeral 16, to allow for the needle movements during the knitting cycle of said course. The rocking rod 10 is next rocked in reverse to return the snapping tackle arm and the device 9 back to their initialpositions to relax the tension onuthe yarn (it being understood that tension on the additionalyarn will in fact be relaxed by reversing of the rocking rod 10 because of the fact that the device 9 acts on the yarn between snapping tackle arm and the needles) at a stage when all the sinkers have been retracted immediately prior to the commencement of a new course so that, as previously referred to, the early part of the movement of the thread carrier for said next course takes up the major part of the slack of the 'yarn'until the carrier has traversed substantially to the extent of its lead over the advancing sinkers (this advance of the sinkers being the usual advance effected by slurcock) whereafter the yarn is sunk for said next course between selvedge needles by one'or more sinkers whilst there is still slack in said 'yarn; as a result of this the old selvedge loops and new selvedge yarn are accurately disposed on the needles for pressing of the beards satisfactorily between them with the advantageous result before referred to. For the remainder' of the course after sinking the selvedge loops the yarn is drawn under normal tension.

The length of additional yarn drawn may be variable to suit requirements by for example adjusting the arins12 about their pivots and/ or by adjusting'the device 9 about the rocking rod 10, suitable adjustable devices being provided for the purpose.

Ifdesired the needles may be employed at a higher level than normal for the purpose before referred to by for example suitable shaping of the conventional needle raising cam.

It'will be appreciated that during fashioning the device which will at this period be advanced to draw'the additional yarn will require additional movement to allow for the normal movement of the fabric during fashioning and this may be accomplished by a suitably-shaped fashioning cam such as -shown at 17 for operating :the, device and which is rendered operative instead of the cam 15 at the required time. i

In one of possible modifications shown in Figures 2 to 4'the device 9 may be independent of the snapping tackle sons to beseparately operated as indicated in Figure 2 to move indesired manner during knitting and be maintained stationary during fashioning leaving the snapping tackle arm 8 to operate in conventional manner. In this arrangement the control of the device 9 may be as above described with reference to constant lead .or it maybe controlled by modified means for variable lead "with the device remaining stationary during fashioning. 7 These modified means-may operate under control of selvedge stops'for varying the -length of additional yarn drawn. Such means may consist of a truck arm 29 of the mechanism 21 being adapted for variation of leverage such as can be effected from said selvedge stops 18, 19 as shown in Figures 3 and 4.

More specifically the truck arm 20 has an extension 20a which is formed with 'a'slot-20b. The rocking rod 1!) has ashort-arm 22 on'itwhich has one end of a link 23 connected to it and the other end 23a of the link 23 is inthe form of--a--pivot whichis'pivoted and slidablein 'said slot 20b. The link 23 has engaged with it a bell crank fork 24 operated by a control rod 25 and the latter ,is operated. through a bell crank26 which is connected to an. operating bell crank 27 one end 27a of which is in the path of the selvedge stop'18 adjustable by a lead screw 29 in well known manner. Consequently, as the selvedge stops are adjusted the'pivot end 23a of the link 23 is adjusted along said slot 20b to vary the truck levers' effective leverage on the link 23.and consequently on the rocking rod 10.

We claim:

1. A method of controlling selvedging in a Cottons patent or other'straightbar knitting machine having a yarn supply, a thread carrier, sinkers, and snapping tackle,in which the leadofthe thread carrier over the sinkers during the latters advancement is variable, which method consists in drawing-off an additional length of yarn from the supply at a location between the snapping tackle and the thread carrier to a length slightly greater than said lead, and in varying the length of additional yarn in accordance with the variationof said lead. V

2. A method of controlling selvedging in a straightbar knitting machine having needles-with end selvedge needles,

"sinkers operated by a slurcock, and a reciprocating thread carrier, to which yarn extends from a supply, wherein during the time that the'thread carrier is stationary at the end of itstraverse there is applied'to theyarn extend ing to the thread carrier a motion drawing-off an additional length of yarn from the supply, and wherein before the thread carrier commences its next traverse the additional length of yarn is relaxed so that it is relaxed yarn which -is taken up by the initial traverse of the carrier, and the additional yarn being of a-length which is predetermined according to thecarrier lead over the slurcock so as-to be sufiicient-to be fed to at least-one sel vedge needle and'allow normally-tensioned-yarn to be fed to the remaining needles.

3. A method of .controlling selvedges as claimed in claim 2 and in a straight-bar knitting machine having dividing sinkers; wherein the additional length of yarn is drawn off'by a deflection-of the yarn extending to the thread carrier, said deflection occurring at a time when the dividing sinkers have been advanced and the yarn is consequentlyUlocked to the needles so that the deflected or. additional length of yarn must be drawn" off from the supply.

4. A method of controlling selvedges as claimed in claim, 2 and in a straight bar knitting machine having dividing sinkers, wherein the. additional length of yarn is drawn off by adeflection of the yarn extending to the thread carrier, said deflection occurring at a timev when the dividing sinkers have been advanced and the yarn is consequently locked to the needles so that the deflected or additional length of yarn must be drawn-oft" from the supply, and wherein the additionallength of yarn is relaxed by discontinuance of thedeflection upon all the providing the other guide, a rocking shaft on which the snapping tackle and the first pivotal arm are mounted, and operating means operable on the rocking shaft whilst the thread carrier is at the end of its traverse to operate the first pivoted arm first to deflect the yarn between the guides and draw-off an additional length from the supply and then to release the additional length of yarn for taking up by the initial part of the next thread carrier traverse.

6. A straight bar knitting machine in which yarn is fed from a supply to needles by a reciprocating thread carrier, which machine comprises the combination of a pair of spaced guides for the yarn between the supply and the thread carrier, a first pivoted arm operable on the yarn between the guides, snapping tackle for the yarn providing one of said guides, a second pivoted arm providing the other guide, a pair of rocking shafts a first of which has the snapping tackle mounted on it and a second of which has the first pivoted arm mounted on it, operating means operable on said second rocking shaft whilst the thread carrier is at the end of its traverse to operate the first pivoted arm first to deflect the yarn between the guides and draw-off an additional length from the supply and then to release the additional length of yarn for taking up by the initial part of the next thread carrier traverse, selvedge stops cooperating with the thread carrier traverse, to control its traverse, and control means operable by the selvedge stops to modify operation of the operating means and automatically vary the length of additional yarn.

7. A straight bar knitting machine in which yarn is fed from a supply to needles by a reciprocating thread carrier, which machine comprises the combination of a pair of spaced guides for the yarn between the supply and the thread carrier, a first pivoted arm operable on the yarn between the guides, snapping tackle for the yarn providing one of said guides, a second pivoted arm providing the other guide, a pair of rocking shafts a first of which has the snapping tackle mounted on it and a sec 0nd of which has the first pivotedarm mounted on it, operating means operable on said second rocking shaft whilst the thread carrier is at the end of its traverse to operate the first pivoted arm to deflect the yarn between the guides and draw-off an additional length from the supply and then to release the additional length of yarn for taking up by the initial part of the next thread carrier traverse, and adjustment means for pre-setting the length of additional yarn.

References Cited in the file of this patent UNITED STATES PATENTS 1,718,835 Rolston June 25, 1929 2,083,333 Lawson June 8, 1937 2,143,485 Janssen Jan. 10, 1939 2,680,364 Wickardt et al. June 8, 1954 FOREIGN PATENTS 121,554 Great Britain Dec. 24, 1918 

